The present invention relates, in general, to a tensioner by which a power transmitting member, e.g. a belt for a traction drive, can be maintained under tension.
Nothing in the following discussion of the state of the art is to be construed as an admission of prior art.
German patent publication no. DE 196 47 225A describes a tensioner which includes a base part restrained against rotation and a pivot arm supporting a roller which is urged against a power transmitting member by a torsion spring arranged between the base part and the pivot arm. The base part has a symmetry axis which defines at the same time the rotation axis for the pivot arm. A damping unit is arranged between the pivot arm and the rotation axis and includes a thrust cone which engages a friction cone of the pivot arm. The thrust cone is urged against the friction cone by a compression spring which is placed between the thrust cone and the base part. This prior art damping unit is complex as a result of the great number of components, and is bulky so as to require a large installation space for realizing a sufficient friction surface between the thrust cone and the friction cone.
It would therefore be desirable and advantageous to provide an improved tensioner to obviate prior art shortcomings and to provide a compact damping unit with increased friction torque, while still being reliable in operation.